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Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - 2DNano (Beyond Graphene: Fundamental properties of 2D materials at the atomic scale)

Teaser

Summary

The project 2DNano aims to synthesize and characterize novel 2D structures on metallic substrates opening ways for the technological exploration of these structures. To this propose the project has been divided in two phases, each of them compromising the following objectives:

Phase1.Synthesis of novel 2D structures on metals
Obj 1.Search of simple and efficient growth methods of 2D layers on noble metal substrates.
Obj 2.Design and investigation of heterostructures combining a semimetal (graphene), a insulator (h-BN) and a semiconductor (SiC).

Phase2.Functionalization of 2D sheets by reactive sites enabling an anchoring of adsorbates
Obj 3.Study of the defects which constitute highly reactive sites for covalent functionalization of the 2D structures.
Obj 4.Chemical functionalization of the 2D layer by metal atoms and macrocyclic systems.

The most important conclusions are:
-We provided a complete, quantitative structure determination of the h-BN and graphene layers on Cu(111) and Ag(111) by AFM, STM and complementary techniques.
-We achieved an in-situ covalent dehydrogenative coupling mechanism yielding â€“for the first timeâ€“ porphines fused to graphene edges.
-We fabricated a layered architecture through the intercalation of functional molecules between the Cu(111) and the h-BN sheet.

Work performed

The synthesis of graphene and h-BN have been achieved on Ag(111) and Cu(111) and explored by AFM/STM. Efforts are underway to synthesize the theoretically predicted semiconductor silicon carbide (SiC). However in order to maximise the outcome of the project, in view of our recent results in graphene on Ag(111), we have adjusted the phases of the project to give priority to the objective 4 related with the chemical functionalization of the 2D layers. Unlike on many other transition-metal supports, the carbon sheets on Ag(111) only interact weakly with the noble metal substrate, resulting in a promising substrate for graphene-edge functionalization. Specifically, we achieved an in-situ covalent dehydrogenative coupling mechanism yielding â€“ for the very first time â€“ tetrapyrroles fused to graphene edges. Currently we are at the process of extending the functionalization approach to other molecules with different functionalities.

In the second half of the project we pursued objectives 2 and 3. In particular, we have initiated an effort to create heterostructures combining graphene and h-BN, as it was envisaged in objective 2.
A detailed evolution of the work plan of the project is present hereafter.

WP1: Setting up of the working environment.
During the first months of the project, the required facilities for the development of the project were implemented (C and Si evaporators, gas line (C2H4), Peltier cooler for Borazine, etc.). The researcher was also trained under the supervision of the Prof. Willi AuwÃ¤rter and collaborators in the use of the new experimental techniques (AFM and XPS). As a result, deliverable D1.1 has been already achieved.

WP2: Synthesis and characterization of novel 2D structures on metals.
The synthesis of graphene and h-BN has been already accomplished on the Cu(111) surface by chemical vapor decomposition (CVD) of ethylene and borazine with good results. For the Ag(111) crystal, different synthesis protocols has been investigated (D2.1) with the results summarize in the image 1.

WP3: Functionalization of 2D sheets by reactive sites enabling an out-of-plane tethering of adsorbates.
We propose the use of reactive sites and unsaturated dangling-bonds produced by the creation of defects, for an out-of-plane tethering of atom and molecular species. The most promising functionalization method for graphene sheets (D3.1) has been shown to be surface-assisted covalent coupling of simple molecular species to graphene edges.

WP4: Promotion, dissemination and networking.
Up to now, where this report is being written, the project has resulted in several publications (D4.1) and the work accomplished has been presented in international conferences. In addition, the researcher has participated in different TUM outreach activities to transfer the knowledge gained to students and extra-academic context.

CONFERENCES

Summer School SFB667
Hohwacht
27â€“ 28 Sep 2017
Invited talk
Porphyrin Molecules at Interfaces: Insight from Scanning Probe Microscopy
M Garnica

19th International Conference on Non-contact Atomic Force
Nottingham
25 â€“ 29 Jul 2016
Oral presentation
Surface-assisted synthesis and edge-functionalization of graphene on Ag(111)
M Garnica et al

3rd European Workshop on Epitaxial Graphene and 2D Materials
Bergisch Gladbach
17 â€“ 21 May 2016
Oral presentation
Surface-assisted synthesis and edge-functionalization of graphene on Ag(111)
M Garnica et al

31st European Conference on Surface Science (ECOSS-31)
Barcelona
31 Aug - 4 Sep 2015
Oral presentation
Comparative atomic-scale scanning probe microscopy study of graphene and boron nitride on noble metals surfaces
M Garnica et al

OUTREARCH ACTIVITIES

Tag der offenen TÃ¼r
21 Oct 2017
Guide lab-tour

Tag der Physikerinnen
17 June 2016

Lange Nacht der Wissenschaft
27 June 2015
Guide lab-tour scanning tunnelling microscope.

Tag der Physikerinnen
23 June 2015

WP5: Management.
Regular meetings are evaluating the practical details, the ex

Final results

Within the last few years, research in the field of 2D material is considered the future prospective to next generation materials science. A process allowing to make these bottom-up fabricated nanostructures available on substrates suitable for further characterization and processing in view of the fabrication of prototypical devices thus is the next logical step. The project therefore advance the European Research Area in a field that is relevant for both, fundamental investigations of the properties of such ultimately precise 2D structures and opening ways for the technological exploration of these structures.

So far, we provided a proof of principle for the functionalization of graphene edges with tetrapyrrolic species by a dehydrogenative coupling reaction directly on a metal surface used for graphene synthesis. We are convinced that our findings will attract widespread attention and open the door to a new research direction relevant for chemical sciences, engineering of advanced materials and achievement of novel functionalities with prospects in various application fields. Specifically, our findings provide a new tool for the controlled modification of surface-anchored nano-graphenes and graphene nanoribbons, structures anticipated to play a significant role in diverse application fields as molecular electronics, sensing or optoelectronics and catalysis.